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yap-6.3/packages/http/js_write.pl
2010-06-23 11:52:34 +01:00

232 lines
6.0 KiB
Prolog

/* Part of SWI-Prolog
Author: Jan Wielemaker, Michiel Hildebrand
E-mail: J.Wielemaker@uva.nl
WWW: http://www.swi-prolog.org
Copyright (C): 2007-2010, University of Amsterdam
VU University Amsterdam
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
As a special exception, if you link this library with other files,
compiled with a Free Software compiler, to produce an executable, this
library does not by itself cause the resulting executable to be covered
by the GNU General Public License. This exception does not however
invalidate any other reasons why the executable file might be covered by
the GNU General Public License.
*/
:- module(javascript,
[ js_call//1, % +Function(Arg..)
js_new//2, % +Id, +Function(+Args)
js_args//1 % +Args
]).
:- use_module(library(http/html_write)).
:- use_module(library(http/json_convert)).
:- use_module(library(http/json)).
:- use_module(library(error)).
:- use_module(library(debug)).
/** <module> Utilities for including javascript
This library is a supplement to library(http/html_write) for producing
JavaScript fragments. Its main role is to be able to call JavaScript
functions with valid arguments constructed from Prolog data. E.g.
suppose you want to call a JavaScript functions to process a list of
names represented as Prolog atoms. This can be done using the call
below, while without this library you would have to be careful to
properly escape special characters.
==
numbers_script(Names) -->
html(script(type('text/javascript'),
[ \js_call('ProcessNumbers'(Names)
]),
==
The accepted arguments are described with js_args//1.
*/
%% js_call(+Term)// is det.
%
% Emit a call to a Javascript function. The Prolog functor is the
% name of the function. The arguments are converted from Prolog to
% JavaScript using js_args//1. Please not that Prolog functors can
% be quoted atom and thus the following is legal:
%
% ==
% ...
% html(script(type('text/javascript'),
% [ \js_call('x.y.z'(hello, 42)
% ]),
% ==
js_call(Term) -->
{ Term =.. [Function|Args] },
html([Function, '(']),
js_args(Args),
html(');\n').
%% js_new(+Id, +Term)// is det.
%
% Emit a call to a Javascript object declaration. This is the same
% as:
%
% ==
% ['var ', Id, ' = new ', \js_call(Term)]
% ==
js_new(Id, Term) -->
{ Term =.. [Function|Args] },
html(['var ', Id, ' = new ', Function, '(']),
js_args(Args),
html(');\n').
%% js_args(+Args:list)// is det.
%
% Write javascript function arguments. Each argument is separated
% by a comma. Elements of the list may contain the following
% terms:
%
% $ Variable :
% Emitted as Javascript =null=
% $ List :
% Produces a Javascript list, where each element is processed
% by this library.
% $ object(Attributes) :
% Where Attributes is a Key-Value list where each pair can be
% written as Key-Value, Key=Value or Key(Value), accomodating
% all common constructs for this used in Prolog.
% $ json(Term) :
% Emits a term using json_write/3.
% $ @(true), @(false), @(null) :
% Emits these constants without quotes.
% $ Number :
% Emited literally
% $ symbol(Atom) :
% Emitted without quotes. Can be used for JavaScript symbols
% (e.i., function and variable-names)
% $ Atom or String :
% Emitted as quoted JavaScript string.
js_args([]) -->
[].
js_args([H|T]) -->
( js_arg(H)
-> ( { T == [] }
-> []
; html(', '),
js_args(T)
)
; { type_error(javascript_argument, H) }
).
js_arg(H) -->
{ var(H) }, !,
[null].
js_arg(object(H)) -->
{ is_list(H) }, !,
html([ '{', \js_kv_list(H), '}' ]).
js_arg(@(true)) --> [true].
js_arg(@(false)) --> [false].
js_arg(@(null)) --> [null].
js_arg(symbol(H)) -->
[H].
js_arg(json(Term)) -->
{ json_to_string(json(Term), String),
debug(json_arg, '~w~n', String)
},
[ String ].
js_arg(H) -->
{ is_list(H) }, !,
html([ '[', \js_args(H), ']' ]).
js_arg(H) -->
{ number(H) }, !,
[H].
js_arg(H) -->
{ atomic(H), !,
js_quoted_string(H, Q)
},
[ '\'', Q, '\''
].
js_kv_list([]) --> [].
js_kv_list([H|T]) -->
( js_kv(H)
-> ( { T == [] }
-> []
; html(', '),
js_kv_list(T)
)
; { type_error(javascript_key_value, H) }
).
js_kv(Key-Value) -->
html(['\'',Key,'\':',\js_arg(Value)]).
js_kv(Key=Value) -->
html(['\'',Key,'\':',\js_arg(Value)]).
js_kv(Term) -->
{ compound(Term),
Term =.. [Key,Value]
}, !,
html(['\'',Key,'\':',\js_arg(Value)]).
%% js_quoted_string(+Raw, -Quoted)
%
% Quote text for use in JavaScript. Quoted does _not_ include the
% leading and trailing quotes.
%
% @tbd Join with json stuff.
js_quoted_string(Raw, Quoted) :-
atom_codes(Raw, Codes),
phrase(js_quote_codes(Codes), QuotedCodes),
atom_codes(Quoted, QuotedCodes).
js_quote_codes([]) -->
[].
js_quote_codes([0'\r,0'\n|T]) --> !,
"\\n",
js_quote_codes(T).
js_quote_codes([H|T]) -->
js_quote_code(H),
js_quote_codes(T).
js_quote_code(0'') --> !,
"\\'".
js_quote_code(34) --> !,
[92,34].
js_quote_code(0'\\) --> !,
"\\\\".
js_quote_code(0'\n) --> !,
"\\n".
js_quote_code(0'\r) --> !,
"\\r".
js_quote_code(0'\t) --> !,
"\\t".
js_quote_code(C) -->
[C].
%% json_to_string(+JSONTerm, -String)
%
% Write JSONTerm to String.
json_to_string(JSON, String) :-
with_output_to(string(String),
json_write(current_output,JSON,[width(0)])).